


The Doctor and the Changeling Child

by Anchestor



Series: Gather round, for this is a tale [1]
Category: Undertale (Video Game)
Genre: Accidental Baby Acquisition, Alternate Universe - Fairy Tale, Dad Gaster, Fae & Fairies, Fairy Tale Style, Gen, baby bones
Language: English
Status: Completed
Published: 2019-10-07
Updated: 2019-10-07
Packaged: 2020-11-26 18:51:08
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,517
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20935055
Author URL: https://archiveofourown.org/users/Anchestor/pseuds/Anchestor
Summary: Once upon a time, there was a skeleton doctor who unexpectedly became a father. One fateful night, the wicked faery queen stole his baby away, leaving behind a fae changeling. Determined to get his child back, the doctor took the false babe, and set on a journey to find the faery hill. There he would both find his son, and rid himself of the imposter child.Gather round, for this is a tale of cunning, a father’s love, and a changeling child.





	The Doctor and the Changeling Child

**Author's Note:**

> Have had this concept in my head for a looooong time. Something about changelings is just so appealing to me. Do note that these ain't your modern day Tinkerbell pixies, the old school faeries can and will Fuck You Up.
> 
> While I marked this to be in the same series as The Knight and the Doctor, you don't have to read them to be in the same continuity, they're independent of each other.
> 
> Also, finally got to use Ao3's best tag: 'Accidental Baby Acquisition' :D

Once upon a time, there was a brilliant young skeleton who’d recently become a doctor. So, having finished his apprenticeship, he returned to the village of his birth. His return coincided with the Midsummer celebrations, a big festival in the village. There were stalls with food and trinkets, games, and in the middle of it all, a grand bonfire. Many returned to the village to celebrate with their family and friends.

As the doctor looked upon the festivities, he saw a fair skeleton maiden in the crowd. She had been a dear friend when they were both children, but she’d since left the village for the big city to learn the trade of tailoring. But now, she spotted the doctor, and came to greet him.

“Gaster! It’s been so long! I hear you’re a doctor these days”, she said with a smile.

“Hello, Arial”, said the doctor cheerfully and hugged her. “How are things in the big wide world? Have you finished your apprenticeship?”

“Yes, and I founded my own shop too!” the tailor said.

So, joining together in the festivities, the two old friends reconnected. The doctor remembered why the tailor had been so dear to him, and how much he enjoyed spending time with her.

So, through the short Midsummer night they danced, they drank, and, intoxicated on the joys of the celebration and the sweet Midsummer mead alike, they found pleasure in each other’s company.

After Midsummer, the tailor left for the big city. The doctor stayed in the village and established a life for himself there.

However, as the summer slowly began to come to its end, he received a letter from the tailor, as grave as it was short.

_‘I am with child. It’s yours.’_

Worry in his heart, the doctor made the journey to the city with haste, and met with the tailor.

“I do not want this child, Gaster”, she said, sorrowful. “I cannot care for it, not now. I just got my shop, I have to work- And I- Even if I wanted a child, I’m just not ready-”

“You do not have to carry it”, the doctor said slowly. “There are midwives who can help you. You never need to bear.”

“No”, she said, shaking her head. “I can’t. I know it’s not a baby yet, just the beginnings of one, but- I cannot bear the thought of cutting a life short before it even begins.”

Tears began to roll down her face.

“What will we do, Gaster?”

“This is all my fault”, the doctor said. “To be so careless, that night- I’m so, so sorry, I never meant to bring this upon you.”

He looked at the tailor, and spoke steadily: “I swear, I will do right by you. If you wish me to, I’ll marry you with honour, and we can raise this child together.”

The tailor snivelled, smiling at him sadly.

“Gaster, you are so very dear to me. But I don’t want you as my husband”, she said. “And I don’t think you truly want me as your wife, either.”

She looked at her hands, thoughtful. “Perhaps we could seek out an old childless couple. One that wished for a baby but could never have one themselves.”

With those words, an idea began to form in the doctor’s head. And as soon as it was complete, he knew in his heart what he most desired.

He took the tailor’s hands in his own.

“The responsibility is shared between us both, but the choice belongs to you, and you alone. If you decide not to carry this child, I’ll bring you to a midwife myself. If you decide to keep it and look after it, with or without me, I’ll do whatever I can to support you both”, he said. Then, he looked at her pleadingly. “But if you will bear this child, but don’t want to raise it, give it to _me_.”

She dried her eyes with her sleeve, looking at the doctor with astonishment. “You would care for it?”

The doctor smiled. “I swear I’m not offering out of duty. I’ve always, _always_ wanted to have a child of my own. This is not how I ever imagined becoming one, but I would love to be the father of this child.”

The tailor pulled the doctor to a close embrace. “Then the baby is yours. I promise to do what I can for you- I’ll send money, and your child will have the finest clothes in all the land!”

The doctor held her in his arms, uncertainty and worry now traded to eager excitement. “Just giving me this child is more than I could ever ask of you.”

So, the tailor and the doctor parted once again, not with misery nor as betrothed, but as friends.

Seasons passed. The colours of summer were washed away by the autumn rains, and the land was frozen in the icy grip of winter. And finally, as the warm spring sun melted away the last drifts of snow, and the flowers and trees were budding with new bloom and leaf, the doctor found himself on the road home with a little baby skeleton in his arms.

The journey was long, and the doctor stopped to rest underneath a blackthorn tree. He pulled back the swaddle to admire his child, and to coo at it as it slept.

But, unbeknownst to him, two beady, black eyes were watching him from the branches. First with mild disinterest, then curiosity, and finally, _greed_.

The doctor made his way home, where he had prepared a nursery for his child. He laid the baby in the crib, and as he was tired from the journey, went to sleep himself as well.

In the middle of the night, he was awakened by the sound of crying. This was not simply the squalling of a baby: the voice carried fright and distress. The doctor rushed to the nursery and was stunned by what he saw.

There was a tall, thin figure, looming over the crib. She as beautiful as she was terrifying: her skin paperwhite, and her eyes black in their entirety. Her long hair was just as black, and it had a shine to it, like it was made of metallic cords so thin you’d cut your hand should you try to card it with your fingers. From her head grew two antlers, like those of a deer, and on her back there were two large insect wings that shimmered with every colour imaginable.

But, to his horror, the doctor saw that she was cradling his child in one arm, his child that was now loudly wailing and desperately trying to squirm out of her grip. Her other hand shone, weaving threads of magic in the air.

She saw the doctor, and gave him a wicked smile. She pressed the baby to her chest, and with a bat of her wings, she was gone.

The doctor could only stand there and shake, trying to grasp what had just happened. He rushed to the nursery window, but the woman was nowhere to be seen.

Then, he heard faint snivelling from the crib.

The doctor went to look into the cot, and lying in it, he saw his child, quietly fussing. But as he gazed upon the baby, he saw its form begin to change. As glimmering magic slowly melted away, his child turned into another baby entirely. The skull, the eyes, the jaw, they were all wrong.

The doctor could not explain what had just happened. Frightened and confused, he took the strange baby, and ran to the cottage of the village midwife.

Once he was able to wake the midwife, he told her what he had seen. He described the winged woman, and the magic turning the child that had looked like his own into one he’d never seen before.

The midwife listened, and when the doctor had finished his tale, she nodded wisely.

“The one that stole your child was the faery queen”, she said gravely. “And the babe she left behind is a changeling.”

“The faery queen? A changeling? I don’t understand”, said the doctor.

“The fair folk take away mortal children sometimes”, the midwife explained. “No-one truly knows why. Perhaps they simply strike their fancy. And when they do, they leave behind a changeling crafted from fae magic. The use their powers to weave an illusion over the changeling, so that the parents can’t tell that their child has been switched with another.”

“I do not want this _changeling_”, the doctor spat with anger. “I want my _true_ child!”

He glared at the changeling, which was unabashedly slumbering in a basket. How dare this… _creature_ take the place of his true son!

“How can I get my child back?”

“Are you certain?” the midwife asked slowly. “The journey will be filled with peril. The faeries are powerful and cunning, and they will not give back what they took easily.”

“Just tell me where to find them”, the doctor said resolutely.

“The fair folk live under a faery hill. I do not know where it is, but I can tell you where to start”, said the midwife. “Once you enter, know not to eat or drink anything they give you, and never tell them your name, for these will put you under their power. The faeries hate bread and the chime of bells. Iron and salt burns them, as those things are too strongly tied to the realm of mortals. A piece of iron nailed to a door will even stop the faeries from entering it. They do enjoy milk, but that is all I know.”

“Thank you”, the doctor said earnestly. “I will make sure to follow your advice. Thank you.”

He then took the changeling, and returned home to prepare to travel. He filled his bag with food as well as things he thought could be useful, and when he was ready, he strapped the changeling to his back.

“I will bring you whence you came-” he muttered bitterly at the changeling, “and take my true son back.”

His Soul filled with determination, he set on his journey to find the faery hill.

The doctor walked with the changeling strapped to his back, through fields and meadows he travelled. As he walked, the child on his back began to cry. However, he paid it no mind.

The doctor saw a cow eating grass in a pasture.

“Gentle cow, most generous of cattle! Do you know the way to the faery hill?” The doctor asked.

“I do not know where it is, for I cannot leave my pasture. But I can tell you which way to search”, the cow said. “But first, tell me, traveller, why does your babe wail so?”

“This child is not mine; it is a _foul_ _changeling_ the wicked faery queen left behind when she stole my _true son_”, the doctor said resentfully. “And I do not know why it wails.”

“Would you show it to me?” the cow asked.

The doctor took the baby in his arms, and the cow looked it over.

“I see”, said the cow. “It is hungry! Here, come milk me, and feed the babe. Then, once it’s calm, I will tell you where to find the faery hill.”

The doctor milked the cow, who told him how to feed the infant, the way a cow mother nurses its calves. As soon as it had the milk bottle, the baby ceased crying. Then, the cow gave the doctor the directions he needed. The doctor thanked the cow, strapped the changeling to his back, and continued on his journey.

He passed by lakes and ponds. As he walked, the child on his back began to cry. He tried to feed it again, but it refused the bottle, so he simply let it bawl.

The doctor came across a river, flowing through the green.

“Powerful river, nourisher of fields! Do you know the way to the faery hill?” The doctor asked.

“I do know where it is, as my waters flow from far and wide, but not precisely. I can only tell you part of the way”, the river said. “But first, tell me, traveller, why does your babe wail so?”

“This child is not mine; it is a changeling the wicked faery queen left behind when she stole my true son”, the doctor said. “And I do not know why it wails. I tried to feed it, but it refused the bottle.”

“Would you show it to me?” the river asked.

The doctor took the baby in his arms, and the river looked it over.

“I see”, said the river. “It is tired. Here, you need to rock it to sleep. Then, once it’s calm, I will tell you where to find the faery hill.”

The river told the doctor how to rock the baby, the way the river’s waves rock boats. It soon ceased crying and fell asleep. Then, the river gave the doctor the directions he needed. The doctor thanked the river, strapped the changeling to his back, and continued on his journey.

He travelled through woods and forests. As he walked, the child on his back began to cry. He tried to feed it again, but it refused the bottle, then he tried to rock it to sleep, but it would not rest. So he simply let it bawl.

The doctor came across a large tree, with a nightingale sitting on its branches.

“Beautiful nightingale, fairest of songbirds! Do you know the way to the faery hill?” The doctor asked.

“That I do, for as I fly through the skies, I see all”, the nightingale said proudly. “But first, tell me, traveller, why does your babe wail so?”

“This child is not mine; it is a changeling the wicked faery queen left behind when she stole my son”, the doctor said hesitantly. “And I do not know why it wails. I tried to feed it, but it refused the bottle; I tried to rock it to sleep but it would not rest.”

“Would you show it to me?” the nightingale asked.

The doctor took the baby in his arms, and the nightingale looked it over.

“I see”, said the nightingale. “The child is scared, perhaps the dark woods are frightening to it. Here, I’ll show you how to sing to it. Then, when it’s calm, I will tell you where to find the faery hill.”

The nightingale sang a lullaby, and the baby in his arms, the doctor sang after it. Slowly the child ceased crying, instead only looking at the doctor as it listened to his song. The doctor met the changeling’s gaze, and for a moment they simply regarded each other.

Then, the nightingale began to speak, and gave the doctor the directions he needed. The doctor thanked the nightingale, strapped the changeling on his back, and continued on his journey.

As night was nearly upon him, he came to a circle of standing stones, surrounding a green mound. On the side of the mound he found a peculiar little wooden door. He thought back on the advice of the midwife, on salt and iron, on bread and bell chime.

The doctor entered the faery hill.

The room behind the door was large and elegant, built of silver in its entirety. In the middle of the room was a grand banquet table, with a plentiful feast laid upon it: wine and roast, and fruits unlike the doctor had ever seen before. Its mere sight was mouth-watering, its scent intoxicating.

In the back of the room, next to a silver door, stood a moth-winged faery servant with a silver key on his hip. He smiled at the doctor pleasantly and bowed.

“Welcome, traveller, to our fine halls! It is rare that we receive visitors from above our hill!” said the faery. “Please, sir, you must be weary from your travels! Sit down and eat, for this feast is prepared specially for you!”

“Thank you kindly, but I must refuse, for I am not hungry”, the doctor said, mindful of all the midwife’s advice. “I am here to meet your queen.”

“Most certainly, you will! But it will take time. As you wait, please, eat!” the faery said with a smile.

For a moment, the doctor thought. Then, he nodded cheerfully.

“Very well! But as it is not very fine to eat alone, won’t you join me? Perhaps have a drink?”

“I am good, thank you”, the faery said.

“Is that so? Surely, your service must be exhausting, and come with little appreciation!” The doctor turned his back on the faery, and reached for two chalices from the table, one silver, one gold. From his bag he pulled out a bottle of thick, creamy milk, and filled both cups. Then, careful to keep his body between the faery servant and his hands, he took a small pouch from his breast pocket. His hands made quick work, careful not to make a sound as the pouches’ content hit the milk. He then turned back to the faery with both chalices in his hand.

“Please, won’t you at the very least toast with me?” The doctor offered the golden chalice to the other.

The faery servant looked at the cup greedily.

“Milk is a delicacy, and rare to come by here”, he said. Then, he smiled wickedly.

“But you are our guest! I must insist that you drink from the finer cup. You have the golden one, and I shall take silver!”

The doctor’s smile dropped. “N-no, it is fine, I wouldn’t want to- as you are my gracious host, you should-”

But the faery had already taken the silver chalice from him.

“Let us toast, then!” he said. “Or is there an issue?”

“N-no- N-none at a-all”, the doctor said shakily, as the faery servant grinned victoriously.

The toasted, and both drank.

As soon as he had drained his cup, the chalice slipped through the doctor’s fingers with a clatter, and he began to hack and cough, dropping to the floor on his knees.

The faery laughed. “Foolish mortal! Did you really think you could trick us? I clearly saw you slip something in the chalice! As if your mortal poisons could even kill us! And now, it’ll be your own doom-”

Suddenly, the faery gagged, and doubled over. Clutching his stomach, he fell to the floor, whining in pain.

The doctor on the other hand stopped coughing, stood up, and dusted off his robes. Then he leaned down, to take the silver key off the faery servants’ belt.

“How..?” the faery said hoarsely. “I saw you poison the chalice... We switched…”

“It was not poison”, the doctor said as he unlocked the silver door. “It was salt. Quite harmless, to us mortals. And it was in both our cups.”

And thusly the doctor entered the silver door.

The next room was even larger and finer as the last, built of gold in its entirety. It was decorated with luscious seats and chairs, perfect for resting. At the back of the room, there was a golden door, and next to it a faery guard. She had butterfly wings and an elegant spear, and on her hip was a golden key.

“Halt!” she said. “Who goes there?”

“Simply a traveller”, the doctor said. “I am here to meet your queen.”

“I cannot let you through”, the guard said. “And only I have the key to the throne room of her majesty.”

“Oh, it is quite alright”, the doctor said in a friendly tone. “I already have a key.”

“What?” the faery guard said, with furrowed brow. “Where did you get a key, when I am it’s only guardian?”

“Why, the friendly faery in the previous room gave it to me”, he answered, casually sauntering to the golden door.

“Impossible!”

“If you don’t believe me, take a look”, to doctor said, pulling a small cloth pouch from his pocket.

The faery took it from him, pried the pouch open, and emptied its contents on the palm of her hand.

Then, she screamed in pain. What she had in her hand was a key, an iron key, and it was burning her. In this moment, the doctor swiftly stole the gold key from her belt. The faery guard dropped the iron key, but it was too late for her to stop the doctor from escaping through the golden door.

He now stood in the throne room of the faery queen.

The hall was grand, made of black stone, glass and gems. Ivy wrapped around tall columns, fireflies trapped in glass orbs shone their cool light, and glimmering streams of water trickled down the walls.

In the centre of the room stood a throne made of ice-blue crystal, and upon the throne sat the beautiful faery queen.

“I must commend you. Few have been able to find our hill, and fewer still to enter my chamber.” She smiled; her mouth filled with sharp teeth. “Won’t you give me your name?”

“…You may call me Ainsel”, the doctor said coolly.

The faery queen laughed. “You are clever, stranger. You would not have come this far if you weren’t.”

“You stole my child”, the doctor said. “_I want him back_.”

The faery queen regarded the doctor, tilting her head as she considered.

“Very well”, she finally said. “I think your persistence deserves a reward. Here.”

She snapped her fingers, and out of thin air, twelve cribs appeared. And in each crib lied a baby, each exactly identical, each one the doctor’s child.

“Go on”, said the faery queen wickedly. “If your true child is so dear to you, take it!”

The doctor looked over the twelve cribs, and glanced at the faery queen, who was watching him with a malevolent smile.

Then, the doctor simply took a piece of bread from his bag, and one by one, offered it to each of the twelve infants. All refused the bread, turning their faces away and squalling. All, except one. This baby cooed and giggled as it saw the doctor, reaching out for him, and joyfully began to gum at the bread as it was offered.

The doctor smiled, taking the baby in his arms.

“Hello, my dear son”, he said, and kissed its forehead. “I’ve come to bring you home.”

“Impressive.”

The doctor turned to look at the faery queen. She snapped her fingers, and the twelve cribs vanished, each of the false infants turning into a small fae imp that scuttled away.

“I must say, this has been quite interesting to observe. I did not think you would be able to beat my illusion magic”, she said. “But I will hold my end of the bargain. You are free to leave with your child. But first-”

She raised her hand and pointed toward the bundle the doctor had on his back.

“Give me back the changeling.”

The doctor nodded. He untied the wrap, releasing the changeling. He then strapped his own child in its place. The changeling in his arms, he approached the faery queen.

Then, he glanced at the baby, and stopped.

“Your magic must be very powerful, to be able to create a child”, said the doctor.

“I am more powerful than you can imagine.”, said the faery queen proudly. “Had you not interrupted my illusion spell, you’d never have been able to tell the difference!”

“Even as he grew?” the doctor asked. “Surely, even your magic is not strong enough to make a child that grows like any other!”

“Oh, it most certainly is”, said the faery queen. “Changelings are unusual when compared to mortal children, but by the time they’re old enough to tell, it is far too late.”

“Then why did you steal my child? You can clearly just make one with your magic.”

“I wanted it.” And from her voice the doctor knew that was all the answer he would ever get.

The doctor looked at the changeling in his arms. “What is to come of it now?”

“It is still small, and cute enough. I’m sure someone in my court will take it on as a pet”, the faery queen answered dismissively. “And when it’s older, it will make a fine servant.”

“A _servant?_ A _pet?_” The doctor’s face twisted in dismay.

“It is just a changeling.”

“But who will feed it when it’s hungry? Who will rock it to sleep? Who will sing to it when it’s scared?” The doctor asked, distressed. “Who will _love_ it?”

“You did not want it either, nor did you care! And you were right not to! It’s just a worthless changeling!” The faery queen stood from her throne; face twisted in terrifying fury. “Now give it to me!”

The doctor clutched the changeling to his chest, shaking his head, indignant.

“I came here to take my child home”, he said. “And with my child I will leave!”

The doctor reached into his pocket, and threw a handful of salt straight into the black eyes of the faery queen. The faery queen screeched and staggered back, enraged, clawing at her eyes. Then the doctor pulled out a bell and began to ring it as loud as possible. The bell chiming, the doctor ran through the golden door, the silver door, and the wooden door, and all faeries he saw as he ran could only scream and cover their ears. He slammed the wooden door shut behind him, quickly took out an iron horseshoe and a hammer, and nailed the horseshoe to the door of the faery hill.

And as the faeries cannot go through a door with iron nailed to it, they were now trapped inside their hill, forever.

The doctor walked the long way back to his village, one baby strapped to his back, one in his arms. When he came home, he placed both of the children side by side on his bed.

The two babies looked at each other curiously. Then, they began to coo and giggle, and rattle softly as skeleton children are prone to do, reaching their little hands towards each other.

The doctor looked at the two with a gentle smile. He stopped to listen to the noises they made. They may have not been able to form words or even syllables yet, but their voices were already distinct in the way only skeleton voices can be.

“You, I will call Sans”, he softly whispered. “And you, Papyrus.”

The doctor bent down and kissed both of them on the forehead.

And so the doctor cared for both the child that was his by blood, and the child that was his by choice. But to him, there was no difference between them, and he never did tell either child that one came from under a faery hill.

When they were hungry, he fed them, when they were tired, he rocked them to sleep, when they were afraid, he sang to them.

And with all his heart, he loved them.

And they all lived happily ever after.

The End.

**Author's Note:**

> I like to imagine Arial comes to visit some time, looks at the two (2) babby's being all cute together, and goes "Hang on a minute... I _distinctly_ remember popping out only ONE of those..."
> 
> Gaster introducing himself as Ainsel is a reference to a Scottish fairy tale, where a kid introduces himself to a fairy as My Own Self, aka Me A'an Sel', aka Ainsel. It's basically the same stunt Odysseys pulled with that cyclops when he said his name was Nobody.
> 
> It's an old fairy lore rule that they can't lie, and you do notice that while they certainly say intentionally misleading things, they never technically say things they don't believe to be true. Like the feast being prepared "specially for you" is true, it's just that it's a trap, not kindness.
> 
> I hope you enjoyed the read! Comments, as always, are much appreciated ^^


End file.
